The present invention relates to air conditioning systems and particularly to an air conditioning system in which a plurality of rooms is air conditioned by an energy flow supplied from a single energy source through respective flow delivery conduits. More particularly, the invention relates to a control system for controlling the cooling or heating power level of each air-conditioned room in response to the temperature of each room with respect to a control point and to its temperature gradient in relation to the temperature and its gradient of another room.
In a conventional heat pump system having a plurality of indoor units supplied with working fluid from a single outdoor unit, a variable speed compressor is employed as a variable capacity energy source and the control algorithm is such that when the temperature of a given room is higher than a reference temperature the compressor is driven at a high speed to increase the total supply energy level and when the temperature decreases to a level below the reference the compressor speed is switched to a low value to decrease the total amount of supply energy. Therefore, the conventional control algorithm is only based upon the room temperature information relative to its reference level for the purpose of varying the total energy level. Actually, however, each of the air-conditioned rooms has different size, so that its cooling or heating power level which is adequate for a large room is unnecessarily greater than is required for small rooms, causing a waste of energy.